/*
 * Author: CHEN Yongyuan (Walter) 1930006025 from OOP(1007)
 * Date: 2022/03/27
 * Description: This is the class of Circle.
 */

public class Circle extends Shape {
	private double radius;

	/**
	 * Constructor of Circle.
	 *
	 * @param x      the x coordinate of the center of the circle
	 * @param y      the y coordinate of the center of the circle
	 * @param radius the radius of the circle
	 */
	public Circle(double x, double y, double radius) {
		super(x, y);
		this.radius = radius;
	}

	/**
	 * Get the area of the circle.
	 *
	 * @return the area of the circle
	 */
	@Override
	public double area() {
		return Math.PI * radius * radius;
	}

	/**
	 * Test
	 */
	public static void testCircle() {
		Circle c1 = new Circle(1.0, 2.0, 3.0);
		System.out.println(c1.getX() == 1.0);
		System.out.println(c1.getY() == 2.0);
		System.out.println(compare(c1.area(), 28.274333882308138));
	}

	/**
	 * Compare two double numbers.
	 *
	 * @param a
	 * @param b
	 * @return true if a and b are equal, false otherwise
	 */
	public static boolean compare(double a, double b) {
		return Math.abs(a - b) < 0.000001;
	}

	/**
	 * toString
	 */
	@Override
	public String toString() {
		return this.getClass().getName() + " has area " + area();
	}
}